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| author | Rostislav Pehlivanov <atomnuker@gmail.com> | 2017-11-25 16:55:44 +0000 |
|---|---|---|
| committer | Rostislav Pehlivanov <atomnuker@gmail.com> | 2017-11-26 02:17:23 +0000 |
| commit | 590136e78da3d091ea99ab5432543d47a559a461 (patch) | |
| tree | 895d1015e229b7401b4d89eb2072d452e995635b | |
| parent | 3154f4417ab56cfd1e978e6abbb68a9f9f7600ed (diff) | |
| download | ffmpeg-590136e78da3d091ea99ab5432543d47a559a461.tar.gz | |
libavcodec/utils.c: simplify avcodec locking with atomics
Also makes it more robust than using volatiles.
Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
| -rw-r--r-- | libavcodec/internal.h | 1 | ||||
| -rw-r--r-- | libavcodec/utils.c | 12 |
2 files changed, 6 insertions, 7 deletions
diff --git a/libavcodec/internal.h b/libavcodec/internal.h index d3310b6afe..1c54966f37 100644 --- a/libavcodec/internal.h +++ b/libavcodec/internal.h @@ -246,7 +246,6 @@ int ff_init_buffer_info(AVCodecContext *s, AVFrame *frame); void ff_color_frame(AVFrame *frame, const int color[4]); -extern volatile int ff_avcodec_locked; int ff_lock_avcodec(AVCodecContext *log_ctx, const AVCodec *codec); int ff_unlock_avcodec(const AVCodec *codec); diff --git a/libavcodec/utils.c b/libavcodec/utils.c index 3a0f3c11f5..c733709171 100644 --- a/libavcodec/utils.c +++ b/libavcodec/utils.c @@ -114,7 +114,7 @@ static int (*lockmgr_cb)(void **mutex, enum AVLockOp op) = NULL; #endif -volatile int ff_avcodec_locked; +static atomic_bool ff_avcodec_locked; static atomic_int entangled_thread_counter = ATOMIC_VAR_INIT(0); static void *codec_mutex; static void *avformat_mutex; @@ -1937,6 +1937,7 @@ int av_lockmgr_register(int (*cb)(void **mutex, enum AVLockOp op)) int ff_lock_avcodec(AVCodecContext *log_ctx, const AVCodec *codec) { + _Bool exp = 0; if (codec->caps_internal & FF_CODEC_CAP_INIT_THREADSAFE || !codec->init) return 0; @@ -1952,22 +1953,21 @@ int ff_lock_avcodec(AVCodecContext *log_ctx, const AVCodec *codec) atomic_load(&entangled_thread_counter)); if (!lockmgr_cb) av_log(log_ctx, AV_LOG_ERROR, "No lock manager is set, please see av_lockmgr_register()\n"); - ff_avcodec_locked = 1; + atomic_store(&ff_avcodec_locked, 1); ff_unlock_avcodec(codec); return AVERROR(EINVAL); } - av_assert0(!ff_avcodec_locked); - ff_avcodec_locked = 1; + av_assert0(atomic_compare_exchange_strong(&ff_avcodec_locked, &exp, 1)); return 0; } int ff_unlock_avcodec(const AVCodec *codec) { + _Bool exp = 1; if (codec->caps_internal & FF_CODEC_CAP_INIT_THREADSAFE || !codec->init) return 0; - av_assert0(ff_avcodec_locked); - ff_avcodec_locked = 0; + av_assert0(atomic_compare_exchange_strong(&ff_avcodec_locked, &exp, 0)); atomic_fetch_add(&entangled_thread_counter, -1); if (lockmgr_cb) { if ((*lockmgr_cb)(&codec_mutex, AV_LOCK_RELEASE)) |